


Birthday Girl

by minxiebutt



Category: Shingeki no Kyojin | Attack on Titan
Genre: F/M, Plot What Plot/Porn Without Plot, Selfcest, male!Nanaba/female!Nanaba
Language: English
Status: Completed
Published: 2020-06-30
Updated: 2020-06-30
Packaged: 2021-03-05 01:07:33
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,864
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25005907
Author URL: https://archiveofourown.org/users/minxiebutt/pseuds/minxiebutt
Summary: It’s probably cosmically fucked up that she’s meeting herself from a parallel world and the two of them mutually seem more interested in sex than the physics that make this possible, but if the universe doesn’t like it then maybe the universe’ll rethink letting her meet other versions of herself in the future.
Relationships: Nanaba/Mike Zacharias, Nanaba/Nanaba (Shingeki no Kyojin)
Kudos: 5





	Birthday Girl

**Author's Note:**

> i wrote this and then didn't re-read or edit so enjoy enjoy!

Nanaba takes in the body before her with a slow, greedy gaze. He stands at just a little taller than herself, familiar wind-tossed hair curling back from his face, a smooth but definitely masculine jaw. His uniform shirt, a pale blue v-neck just like her own, dips low enough to show the rise of his pectoral muscles and a dusting of very fine, white-blonde chest hair. Without all the gear straps, his shirt is lopsidedly untucked, and her fingers itch to pull the rest of the cotton out of his trousers, to lift it up and find what lies beneath. 

She looks back up to his face and guesses that if she had a twin brother, he might look like this. But she’s an only child.

“Handsome,” she finally judges, cutting her eyes to where Mike watches her appraising her ‘surprise’ from the windowsill. The panes are pushed open, letting in the late June breeze to relieve the headquarters of the stuffiness that lingers well into the early evening, and Mike is half sitting on the wide sill, half leaning, no doubt nosing at the fresh air. 

“Thank you,” her male counterpart sheepishly responds. “You’re quite attractive, too.”

Nanaba tilts her head at him, curious. She’d been content to allow her birthday to pass unremarked, grateful only to have another to celebrate, especially after Utgart, but Mike had dragged in this striking fellow from walls-know-where, with no explanation as to why he shares Nanaba’s name and appearance, calling him something of a treat for her to indulge in. 

“We’re vain, aren’t we?” She smirks at the boy Nanaba. 

“Perhaps,” he admits. 

Nanaba closes the distance between them and settles her palms on Nanaba’s firm pecs, asking him, “I’ll assume you’ve taken lovers before?”

His gaze flicks to Mike for a brief moment and he says, “Yes. We’re identical, after all.”

She brushes her thumbs over his nipples, smiling at his flinch, whispering, “We’ve both fucked our Mikes, haven’t we?”

“I think we would in any life,” Nanaba responds, his voice turning to gravel when he drops it that low. 

Instead of answering, she raises her hands to coax his uniform jacket from his shoulders, and he lets it drop to the floor. She lifts the sleeve on his right side and sees a barbed wire scar wrapping around his upper arm, a perfect match to her own scar, the only remaining proof that surgeons dug out shrapnel and sewed her shut again. Sewed them both shut. 

“Undress,” she tells the boy Nanaba, turning toward the window to where Mike is silently observing the entire exchange with excruciating stoicism. With his eye contact locked with hers, she begins to undo the straps of her gear, throwing them into a heap at his feet, poking a sleeping bear. Whether this is some sort of trick, she’s not going to guess how Mike is pulling it off. She feels something beyond kinship to the boy Nanaba; she feels like she _ is him,  _ somehow, and that he is also her, that they are indeed one and the same but split by sibling universes. It’s probably cosmically fucked up that she’s meeting herself from a parallel world and the two of them mutually seem more interested in sex than the physics that make this possible, but if the universe doesn’t like it then maybe the universe’ll rethink letting her meet other versions of herself in the future. 

Nanaba unclasps the straps around her legs and waist, kicks off her boots so she can step out of the straps completely, and then shimmies her white pants down her thighs into a neat puddle. Mike continues to watch her without reaction, and with a huff, she twists around to show off for an obviously appreciative boy. 

The boy Nanaba watches her undress with the same greedy gaze that she’d just been admiring him with. She pulls her shirt over her head, the binder following suit shortly, and he steps forward, wrapping his fingers around the drawstring of her briefs and tugging the knot undone. With a gentle push, those too puddle on the floor, the two of them now stark naked. 

She straightens her shoulders and tilts her chin up, smiling when Nanaba wastes no time descending onto her mouth, his own lips parting with expectation. He kisses just the same way she does, with a gently licking tongue tickling the roof of her mouth, and she latches onto it with her teeth. The bite isn’t painful, but he pulls back regardless, a lovely gasp leaving him.

Behind her, at the window, Mike makes his presence known with an ambiguous sigh. Nana sticks her ass out to shake it at him, reminding him that this could quite agreeably become a threesome, but the boy Nanaba takes her by surprise, filling his hands with her rump and pulling her against him, sliding one of his legs between hers. Already, just from a bitten kiss, he’s getting hard. She reaches between them and takes his cock, thumbing at the foreskin. He hisses, hips shaking.

“When’s the last time someone touched you?” She teases, yanking on his length just to wring another pretty sound out of him. The boy’s a bottom, no doubt, and very vocal; they’re supposed to be identical after all.

“This morning!” He groans, rocking into her grasp, dropping his head onto her shoulder as she stuffs her thumbnail into his slit, his body filling with shivers. “Oh, god, this morning.”

It almost knocks him off his feet when she drops to her knees, getting first an eyeful of his cock and then a mouthful. It’s a deep pink, velvet smooth, pubic hair shaved away, putting him on full display. She starts a long lick at the head and runs her tongue all the way along the stubble until she reaches his belly button. He’s so  _ sensitive, _ so cutely sensitive, already a quivering mess, dick all hot and stiff. Nana gets back down, wrapping her hand around the base, pumping slowly and sucking on the fat head as if it were a sugar candy.

The moan that involuntarily rips from his throat is so loud that she’s not surprised to hear the window close. When she pulls back from Nanaba’s cock with a lewd  _ pop-- _ though a string of thick spit connects her tongue to the tip-- her eyes lock with Mike’s. His expression is blank but his cheeks are flushed with voyeuristic enjoyment.

Nana focuses on the boy before her again, letting go of his exuberant erection and going all the way down on him, groaning when the ridge of his head tickles behind her tonsils. His hands are wild in her hair, a tremor identifiable even through a clench. If he’s not gonna last much longer, then she needs to get him on his back.

Circling her thumb and forefinger like a makeshift cockring, she looks up at him, delighting in the bliss of the gaze that meets her own. 

“Get on your back,” she murmurs, keeping eye contact and giving Nanaba’s cock a kiss on the slit. He nods to her, swallowing.

Nana looks over her shoulder at Mike while her counterpart situates himself on the bed, his head on the pillows. Mike is watching her, his eyes heavy, as she approaches the boy, ceremoniously swinging one knee up onto the bed, smiling as his eyes immediately drop between her legs in the process of her straddling him. She remains up on her knees above him, looking him over, his body lean, somewhat boyish, somewhat feminine. If it weren’t for the dick standing at absolute attention below, she’d call his features slightly ambiguous. Figures though-- she is often mistaken as male, so maybe in his universe he’s mistaken for female from time to time. 

Despite the flourish with which she climbed upon the bed, Nana sinks down on him without show. Barely an inch into her, the boy closes his eyes, his jaw dropping open, a long moan dissolving into breathy whimpers as she seats herself fully. Prying his hands away from where he’s fisting at her blankets, she settles his hands on her hips, encouraging him to move her, show her the rhythm he wants. She is wholly unsurprised that they want the same. With this penetration pleasuring them both, a chorus of moans and gasps and throaty “yes” and “god, _ fuck” _ fill the room, bouncing all around their heads. A particular circling of her hips, and she looks to Mike between heavy lids, licking her lips at the sight of him biting one palm while simultaneously palming his erection through his canvas trousers.

Slow at first, she works herself over with Nanaba’s cock, but what begins as skillful angling of hips devolves into animalistic thrusts within a few minutes, one thing in both of their minds: the ferocious need to cum. It’s clouding over both of them, bring them both, and with a shared shout, she stills and he pulls her hips down to bury his cock deep. She tolerates him inside her for only a moment as they come down, and then they’re both hissing with oversensitivity, needing a moment. 

“Fuck,” she mewls, raising off of him. His cum coats his cock and then smears over his upper thigh. Nana dips her fingers into the puddle, painting a letter N on his skin that shines in the sunlight. With her clean hand, she cups the back of Nanaba’s head and dives down to kiss him, lazy after orgasm. Against his chin, she whispers, “You like it on your back?”

He shakes his head, tongue darting out to poke her nose. “Doggy style.”

“What a coincidence,” she purrs. She’s already on her knees, it’s the slightest adjustment to curl her arms beneath her chest, pressing her face into the blankets right next to his, lifts her ass as high as she can get it. He half-groans, half-laughs, one of his hands finding his cock to stroke it back to life-- good to know they both have an adolescent libido. 

For hours, they’re an atrocious tangle of identical limbs and desires, Nana doing her best to absolutely wring the boy bone-dry and eventually succeeding after a strenuous round of jackhammering, settling for his skilled fingers when his cock finally gives up the ghost. 

Mike keeps up his vigilant guard, only departing once the pair of Nanabas seem to be at rest-- though, admittedly, they get one more quickie in the time he’s gone-- and returning twenty minutes later, looking less flustered and holding a plate with half of a carrot cake. He sits on the bed, and Nana sits up from spooning the boy.

“Thought since he’ll be here ‘til morning, you might’ve wanted some energy,” Mike says, hushed tones. 

“Morning, hm?” Nana takes a fork when Mike offers one and then slides it into the cake, offering it to Nanaba where he remains lying on his side. He lifts his head and accepts her offer. “We’ll definitely need desert to keep our strength up, won’t we?”

“Mmhm,” he agrees, licking frosting from the corner of his mouth. “We’d better make the most of our time together.”

  
  



End file.
